Induction system for small watercraft

Abstract

A small watercraft includes an internal combustion engine having an air induction system that minimizes the volume of water delivered to the combustion chambers and maintains a generally low center of gravity. The induction system includes an intake silencer which is divided into an upstream chamber and a downstream chamber. The chambers communicate with each other through a passageway. The upstream chamber has an inlet for drawing air from the engine compartment, and the downstream chamber has an outlet communicating through a conduit with an intake chamber. The inlet and outlet are positioned in an upper portion of the silencer and the passageway is positioned in a lower portion of the silencer. Thus, air flowing through the silencer must change direction and water in the air will be separated from the air flow and deposited on the inner walls of the silencer. Each of the upstream and downstream chambers has a drain port through which water may be evacuated. a plurality of intake pipes extend generally upwardly from the intake chamber and communicate with corresponding combustion chambers.

What is claimed is:  
     
       1. A small watercraft comprising a hull having a longitudinal axis and an engine compartment, an internal combustion engine supported within the engine compartment, the engine comprising an engine body having an upper surface and a plurality of combustion chambers, a propulsion device supported by the hull and driven by the engine, and an induction system adapted to conduct air from the engine compartment to each of the combustion chambers, the induction system comprising an intake silencer and an intake chamber, the intake silencer and the intake chamber communicating with each other through a connection pipe, the intake silencer having an inlet, the inlet communicating with the engine compartment, the intake chamber communicating with the combustion chambers through a corresponding plurality of intake pipes, the intake pipes extending generally upwardly from the intake chamber such that the intake chamber is positioned generally lower than the upper surface of the engine body. 
     
     
       2. The small watercraft of  claim 1 , wherein each of the intake pipes has an inlet end arranged within the intake chamber and spaced from a wall of the intake chamber. 
     
     
       3. The small watercraft of  claim 2 , wherein the intake chamber is vertically lower than the combustion chambers. 
     
     
       4. The small watercraft of  claim 1 , wherein the intake chamber has a bottom surface having a collection portion, and the bottom surface is adapted to direct fluid to the collection portion. 
     
     
       5. The small watercraft of  claim 4 , wherein the bottom surface has a drain port positioned in the collection portion. 
     
     
       6. The small watercraft of  claim 5 , wherein the drain port is connected to a one-way valve. 
     
     
       7. The small watercraft of  claim 5 , wherein the drain port communicates with a pump. 
     
     
       8. The small watercraft of  claim 7 , additionally comprising a fluid sensor in the intake chamber, the fluid sensor communicating with a controller adapted to actuate the pump when the fluid sensor detects fluid in the intake chamber. 
     
     
       9. The small watercraft of  claim 1 , wherein the intake silencer comprises an upstream chamber, a downstream chamber, and a passageway between the upstream chamber and downstream chamber, and the inlet opens into the upstream chamber, and a connection pipe inlet opens into the downstream chamber. 
     
     
       10. The small watercraft of  claim 9 , wherein the inlet, the connection pipe inlet, and passageway define a tortuous flow path through the intake silencer. 
     
     
       11. The small watercraft of  claim 10 , wherein the inlet and the connection pipe inlet are positioned in one of an upper portion and a bottom portion of the intake silencer and the passageway is positioned in the other of the upper portion and the bottom portion of the intake silencer. 
     
     
       12. The small watercraft of  claim 9 , wherein each of the upstream chamber and downstream chamber comprise a drain port. 
     
     
       13. The small watercraft of  claim 12 , wherein a collection area is defined adjacent the drain port of each of the upstream and downstream chambers, and the bottom surfaces of the upstream and downstream chambers are each adapted to direct fluid to the respective collection area. 
     
     
       14. The small watercraft of  claim 13 , wherein at least one of the upstream and downstream chambers comprises a splash plate. 
     
     
       15. The small watercraft of  claim 14 , wherein the splash plate is spaced from the bottom surface. 
     
     
       16. The small watercraft of  claim 14 , wherein the splash plate has at least one opening formed therethrough. 
     
     
       17. The small watercraft of  claim 12 , wherein the drain port is connected to a one-way valve. 
     
     
       18. The small watercraft of  claim 12 , wherein the drain port communicates with a pump. 
     
     
       19. The small watercraft of  claim 1 , wherein the inlet is formed through a side wall of the intake silencer, which side wall faces the engine body. 
     
     
       20. The small watercraft of  claim 1 , wherein the intake silencer comprises a connection pipe inlet, and the connection pipe inlet is spaced from an inner surface of the intake silencer. 
     
     
       21. The small watercraft of  claim 1 , additionally comprising a throttle valve between the intake silencer and the intake chamber. 
     
     
       22. The small watercraft of  claim 1 , wherein the inlet is vertically higher than the combustion chambers. 
     
     
       23. The small watercraft of  claim 22 , wherein the intake silencer is generally vertically higher than the intake chamber. 
     
     
       24. A small watercraft comprising a hull having a longitudinal axis and an engine compartment, an internal combustion engine supported within the engine compartment, the engine including an engine body and a crankcase, a plurality of combustion chambers defined within the engine body, an output shaft disposed within the crankcase and arranged generally parallel to the longitudinal axis of the hull, a propulsion device supported by the hull and driven by the engine, and an induction system adapted to conduct air from the engine compartment to each of the combustion chambers, the induction system comprising an intake silencer, the intake silencer comprising an upstream chamber, a downstream chamber, and a passageway communicating with the upstream and downstream chambers, the upstream chamber and downstream chamber being disposed side-by-side and being separated by a dividing wall, the passageway extending through the dividing wall and being spaced from a bottom surface of the upstream chamber and a bottom surface of the downstream chamber, the upstream chamber comprising an inlet communicating with the engine compartment, the downstream chamber having an outlet, and the inlet and the outlet are positioned in one of an upper portion and a lower portion of the intake silencer and the passageway is positioned in the other of the upper portion and the lower portion of the intake silencer. 
     
     
       25. The small watercraft of  claim 24 , wherein a tortuous flow path is defined through the intake silencer between the inlet and the outlet. 
     
     
       26. The small watercraft of  claim 24 , wherein each of the upstream chamber and the downstream chamber have a drain port. 
     
     
       27. The small watercraft of  claim 26 , wherein a collection area is defined adjacent the drain port of each of the upstream and downstream chambers, and a bottom surface of each of the upstream and downstream chambers is adapted to direct fluid to the respective collection area. 
     
     
       28. The small watercraft of  claim 27 , wherein at least one of the upstream and downstream chambers comprises a splash plate, wherein the splash plate is spaced from the bottom surface. 
     
     
       29. The small watercraft of  claim 28 , wherein the splash plate has at least one opening formed therethrough. 
     
     
       30. The small watercraft of  claim 26 , wherein the drain port is connected to a one-way valve. 
     
     
       31. The small watercraft of  claim 26 , wherein the drain port communicates with a pump. 
     
     
       32. The small watercraft of  claim 24 , wherein the inlet and outlet are each spaced from an inner surface of the intake silencer. 
     
     
       33. A small watercraft comprising a hull having a longitudinal axis and an engine compartment, an internal combustion engine supported within the engine compartment, the engine including an engine body and a crankcase, a plurality of combustion chambers defined within the engine body, an output shaft disposed within the crankcase and arranged generally parallel to the longitudinal axis of the hull, a propulsion device supported by the hull and driven by the engine, and an induction system adapted to conduct air from the engine compartment to each of the combustion chambers, the induction system comprising an intake silencer, the intake silencer comprising an upstream chamber, a downstream chamber, and a passageway communicating with the upstream and downstream chambers, the upstream and downstream chambers being disposed side-by-side and being separated by a dividing wall, the upstream chamber comprising an inlet communicating with the engine compartment, the downstream chamber having an outlet, and each of the upstream chamber and the downstream chamber have a drain port. 
     
     
       34. The small watercraft of  claim 33 , wherein a collection area is defined adjacent the drain port of each of the upstream and downstream chambers, and a bottom surface of each of the upstream and downstream chambers is adapted to direct fluid to the respective collection area. 
     
     
       35. The small watercraft of  claim 34 , wherein at least one of the upstream and downstream chambers comprises a splash plate, wherein the splash plate is spaced from the bottom surface. 
     
     
       36. The small watercraft of  claim 35 , wherein the splash plate has at least one opening formed therethrough. 
     
     
       37. The small watercraft of  claim 33 , wherein each of the drain ports is connected to a one-way valve. 
     
     
       38. The small watercraft of  claim 33 , wherein each of the drain ports communicates with a pump. 
     
     
       39. A small watercraft comprising a hull having a longitudinal axis and an engine compartment, an internal combustion engine supported within the engine compartment, the engine including an engine body and a crankcase, a plurality of combustion chambers defined within the engine body, an output shaft disposed within the crankcase and arranged generally parallel to the longitudinal axis of the hull, a propulsion device supported by the hull and driven by the engine, and an induction system adapted to conduct air from the engine compartment to each of the combustion chambers, the induction system comprising an intake silencer, the intake silencer comprising an upstream chamber, a downstream chamber, and a passageway communicating with the upstream and downstream chambers, the upstream chamber comprising an inlet communicating with the engine compartment, the downstream chamber having an outlet, wherein the inlet and outlet are each spaced from an inner surface of the intake silencer. 
     
     
       40. The small watercraft of  claim 39 , wherein the upstream chamber and downstream chamber are disposed side-by-side. 
     
     
       41. The small watercraft of  claim 40 , wherein the upstream chamber and downstream chamber are separated by a dividing wall.